package com.weblog;

import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import com.alibaba.druid.util.StringUtils;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.Claim;
import com.auth0.jwt.interfaces.DecodedJWT;

public class token {
	
	public static void main(String[] args) {
		String token = CreateToken(123L);
		System.out.println(token);
		
		Map<String, Claim> map = verifyToken(token);
		System.out.println(map.get("aud").asString());
		System.out.println(map.get("iss").asString());

		System.out.println(getAppUID(token));
	}

	
	 /**
     * APP登录Token的生成和解析
     * 
     */

    /** token秘钥，请勿泄露，请勿随便修改 backups:JKKLJOoasdlfj */
    public static final String SECRET = "JKKLJOoasdlfj1";
    /** token 过期时间: 10天 */
    public static final int calendarField = Calendar.DATE;
    public static final int calendarInterval = 10;
	
	private static String  CreateToken(Long user_id) {
		Date iatDate = new Date();
		// expire time
		Calendar nowTime = Calendar.getInstance();
		nowTime.add(calendarField, calendarInterval);
		Date expiresDate = nowTime.getTime();

		// header Map
		Map<String, Object> map = new HashMap<>();
		map.put("alg", "HS256");
		map.put("typ", "JWT");

		// build token
		// param backups {iss:Service, aud:APP}
		String token = JWT.create().withHeader(map) // header
				.withClaim("iss", "Service") // payload
				.withClaim("aud", "APP")
				.withClaim("user_id", null == user_id ? null : user_id.toString())
				.withIssuedAt(iatDate) // sign time
				.withExpiresAt(expiresDate) // expire time
				.sign(Algorithm.HMAC256(SECRET)); // signature
		
		return token;
	}
	
	
	/**
     * 解密Token
     * 
     * @param token
     * @return
     * @throws Exception
     */
    private static Map<String, Claim> verifyToken(String token) {
        DecodedJWT jwt = null;
        try {
            JWTVerifier verifier = JWT.require(Algorithm.HMAC256(SECRET)).build();
            jwt = verifier.verify(token);
        } catch (Exception e) {
            // token 校验失败, 抛出Token验证非法异常
        }
        return jwt.getClaims();
    }
    
    /**
     * 根据Token获取user_id
     * 
     * @param token
     * @return user_id
     */
    private static Long getAppUID(String token) {
        Map<String, Claim> claims = verifyToken(token);
        Claim user_id_claim = claims.get("user_id");
        if (null == user_id_claim || StringUtils.isEmpty(user_id_claim.asString())) {
            // token 校验失败, 抛出Token验证非法异常 返回登录页面  git提交测试
        }
        return Long.valueOf(user_id_claim.asString());
    }
	
}
